In addition, it is stated in the article “Visual Languages—an Inexorable Trend in Industry” (Josef Hübl, PLCs/IPCs/Drives—Convention Volume, pp. 88–95, Nov. 23–25, 1999, Nuremberg, Verlag, Hüthig GmbH, Heidelberg) that control flowcharts and data-flow diagrams for control of automation functions may be created with the help of graphical editors.
It is conventional to use debuggers as auxiliary programs for troubleshooting and error localization in programming environments (Volker Claus et al., DUDEN Informatik 2nd expanded edition. page 188, Dudenverlag, 1993).
With the debuggers available today, however, the holding points or breakpoints, necessary for user-controlled execution of the program to be tested, are converted in the processor code. Therefore, the step-by-step or successive execution of the program, which is necessary for debugging, takes place on a low level of abstraction. Thus, the program is inflexible for a user with regard to visualization, for example.
The graphical input means and graphical editors available today for programming throughout industrial controllers do not provide adequate support with regard to adaptive mechanisms for the hardware configuration on which an application is based. In the graphical editor, the user is provided only with a rigid and restricted set of programming language commands.
In addition, the graphical input means and graphical editors available today for programming industrial controllers, support either dedicated programming to control an industrial process programmable controller (PLC), or programming the motion controller of a processing machine or production machine. Creation of programs for both fields of applications is not adequately supported by the existing flowchart editors.
Another disadvantage of the flowchart editors used today for programming industrial automation functions is that the diagrams created with these editors are either converted directly to executable processor code or to ASCII code, and must subsequently be interpreted in the respective target system through a run time-intensive process. This system is not just inflexible with regard to porting and transfer of programs to other systems or machines, but also restricts the user's debugging options.
Additional disadvantages of existing flowchart editors include the fact that only a limited, rigid and inflexible library of icons is available, and that the processing sequence of icons and the corresponding function blocks is predetermined. Furthermore, existing flowchart editors frequently offer only a limited number of possibilities for formulating synchronization mechanisms, although such mechanisms are frequently required, in particular for programming applications in industrial automation.